A diet rich in healthy and plant-based foods is linked with the presence and abundance of certain gut microbes that are also associated with a lower risk of developing conditions such as obesity, Type 2 diabetes, and cardiovascular disease, according to recent results from a large-scale international study that was co–authored by Dr Andrew T Chan, from Harvard-affiliated Massachusetts General Hospital (MGH). The outcomes from the PREDICT 1 (Personalized Responses to Dietary Composition Trial 1) metagenomic study were featured in the paper, ‘Microbiome connections with host metabolism and habitual diet from 1,098 deeply phenotyped individuals’, published in Nature Medicine.
"This study demonstrates a clear association between specific microbial species in the gut, certain foods, and risk of some common diseases," explained Chan, a gastroenterologist, chief of the Clinical and Translational Epidemiology Unit at MGH, and professor of medicine at Harvard Medical School. "We hope to be able to use this information to help people avoid serious health problems by changing their diet to personalise their gut microbiome."
The PREDICT 1 study analysed detailed data on the composition of participants' microbiomes, their dietary habits, and cardiometabolic blood biomarkers. The researchers found strong evidence that the microbiome is linked with specific foods and diets, and that, in turn, its composition is also associated with levels of metabolic biomarkers of disease. Further, the microbiome has a greater association with these markers than other factors, such as genetics.
"Studying the interrelationship between the microbiome, diet and disease involves a lot of variables because people's diets tend to be personalized and may change quite a bit over time," added Chan. "Two of the strengths of this trial are the number of participants and the detailed information we collected."
PREDICT 1 is an international collaboration to study links between diet, the microbiome, and biomarkers of cardiometabolic health. The researchers gathered microbiome sequence data, detailed long-term dietary information, and results of hundreds of cardiometabolic blood markers from just over 1,100 participants in the UK and the US.
The researchers found that participants who ate a diet rich in healthy, plant-based foods were more likely to have high levels of specific gut microbes. The makeup of participants' gut microbiomes was strongly associated with specific nutrients, foods, food groups, and general dietary indices (overall diet composition). The researchers also found robust microbiome-based biomarkers of obesity as well as markers for cardiovascular disease and impaired glucose tolerance.
For example, having a microbiome rich in Prevotella copri and Blastocystis species was associated with maintaining a favourable blood sugar level after a meal. Other species were linked to lower post-meal levels of blood fats and markers of inflammation. The trends they found were so consistent, the researchers believe that their microbiome data can be used to determine the risk of cardiometabolic disease among people who do not yet have symptoms, and possibly to prescribe a personalised diet designed specifically to improve someone's health.
"We were surprised to see such large, clear groups of 'good' and 'bad' microbes emerging from our analysis," said Dr Nicola Segata, professor and principal investigator of the Computational Metagenomics Lab at the University of Trento, Italy, and coordinator of the analysis of the microbiome data in the study. "And it is intriguing to see that microbiologists know so little about many of these microbes that they are not even named yet."